Parts feed device

ABSTRACT

A parts feeder for a robot has a selection zone accessible to the robot, a device for changing the orientation and/or the position of the parts stochastically, and a device with a parts recirculation element for recirculating the parts. The device for changing the orientation and/or the position of the parts stochastically is a vibrating platform constructed at the same time as a selection zone vibrating platform can be brought relative to each other into two different positions in such a way that in the first position the vibrating platform can be brought relative to each other into two different positions in such a way that in the first position the vibrating platform can be loaded with parts from the parts recirculation element and in the second position the parts which fall down from the vibrating platform can be collected by the parts recirculation element. By constructing the parts recirculation element firstly as a parts reservoir for loading the vibrating platform with parts from the parts recirculation element and, secondly, as a collecting element for parts falling down from the vibrating platform, the parts feeder can manage without a parts transport device for horizontal conveyance of the parts, such as conveyor belts, linear rails or the like. This permits an extremely simple and space-saving construction of the parts feeder.

This application is the national phase under 35 U.S.C. §371 of PCTInternational Application No. PCT/CH00/0024 which has an Internationalfiling date of May 3, 2000, which designated the United States ofAmerica.

FIELD OF THE INVENTION

The invention relates to a parts feeder according to the preamble ofclaim 1.

PRIOR ART

For the transfer of parts, which are supplied in the form of bulk goodsin a storage container, to a robot, the parts as a rule firstly have tobe separated from one another (that is to say individualized) andbrought into an orientation and position suitable for the transfer tothe robot. This task is carried out by parts feeders, as they are known(also referred to as feed systems). A parts feeder accordingly picks upparts in the form of bulk goods, separates the parts and transfers themin a suitable orientation and position to a robot. The robot grips thesuitably oriented parts in a selection zone of the parts feeder andsubsequently transfers them for further processing and/or mounting to amounting system, a processing station or the like. In this connection, arobot is to be understood as any kind of apparatus for gripping parts ina favorable orientation and position and subsequently conveying themaway from the point at which they are gripped or selected.

Most customary parts feeders comprise a mechanical filter in the form ofa vibrating pot which can be rotated about a vertical axis to separatethe parts and to orient and position the same. The pot is provided withinternal, spiral volutes. Arranged along the volutes are a large numberof mechanical guide elements and barriers. On account of the vibratingrotational movement of the pot, the parts are transported upward alongthe volutes to the outlet of the pot. By means of the barriers and guideelements, only parts in a specific orientation are transported as far asthe outlet of the pot, the remainder fall back onto the bottom of thepot in order to begin a renewed transport operation along the volutes.From the outlet of the pot, the parts are typically conveyed onward vialinear rails, in order to maintain their separation and orientation.

The mechanical filters in the form of vibrating pots have thedisadvantage that they are tailored specifically to specific parts. Theyare extremely inflexible in relation to changes in the parts. In theevent of a modification to the geometric form of the parts, most oftenthe entire vibrating pot has to be redesigned, constructed and tested.In addition, both the volutes of vibrating pots and the linear railsadjacent to the pots are susceptible to blockages as a result ofdefective and/or particularly unfavorably positioned parts, inparticular when the latter have a complicated geometric form.

In the U.S. Pat. No. 5,687,831 (Adept Technology), a parts feeder isdescribed which, as compared with vibrating pots, exhibits improvedflexibility in relation to different parts forms. The parts feederaccording to U.S. Pat. No. 5,687,831 comprises an essentially horizontaltransport section on which the parts are transported to a selectionzone. In the selection zone, favorably oriented and arranged parts aredetected by means of a video camera and are subsequently gripped by arobot and transferred to a mounting system. The parts that are notselected are guided back to the start of the transport section by meansof a recirculation system for a renewed passage through the partsfeeder. While they are being fed back, the orientation and the positionof the parts are changed in order that they may be oriented favorablyduring the next pass and selected in the selection zone.

Although the parts feeder according to U.S. Pat. No. 5,687,831 is to acertain extent flexible in relation to different parts forms, it isrelatively complicated in design terms and requires a considerableamount of space for the arrangement of the transport section, theselection zone and the recirculation system.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a parts feeder whichis simple in design terms, space-saving and flexible in relation todifferent parts forms.

The object is achieved as defined by the features of the independentpatent claims.

According to the invention, a parts feeder for a robot has a selectionzone accessible to the robot, a device for changing the orientationand/or the position of the parts stochastically, and a device with aparts recirculation element for recirculating the parts. The device forchanging the orientation and/or the position of the parts stochasticallyis a vibrating platform constructed at the same time as a selectionzone. The parts recirculation element and the vibrating platform can bebrought relative to each other into two different positions in such away that in the first position the vibrating platform can be loaded withparts from the parts recirculation element and in the second positionthe parts which fall down from the vibrating platform can be collectedby the parts recirculation element.

In the course of the present description and the claims, a partsrecirculation element is always to be understood as an element providedto recirculate parts. Such a parts recirculation element can beconstructed, for example, as a separate section, as a zone or partscarrying area which can be moved with respect to the vibrating platform,as a recirculation container constructed so as to accommodate a fewparts, or as a storage container constructed so as to accommodate alarge quantity of parts.

The parts recirculation element is used firstly, in a first position, toload the vibrating platform with parts. As soon as the vibratingplatform has been loaded with a sufficient number of parts, the partsrecirculation element and the vibrating platform are brought relative toeach other into a second position, in which the same parts recirculationelement is used to collect parts which fall down from the vibratingplatform during the vibration. At the same time, the vibrating platformserves as a selection zone for the parts feeder, that is to say theparts are gripped by the robot on the vibrating platform and conveyedaway. (The actions of gripping the parts and conveying them away is alsoreferred to as selecting the parts.) If the number of parts remaining onthe vibrating platform falls below a minimum number, the partsrecirculation element and the vibrating platform are brought relative toeach other into the first position again, in order to load the vibratingplatform again with parts from the parts recirculation element. As aresult, the parts which have fallen down from the vibrating platformonto or into the parts recirculation element are guided back to thevibrating platform and are therefore recycled. The parts recirculationelement therefore serves alternately as a parts reservoir for loadingthe vibrating platform with parts and as a collecting element forcollecting the parts that fall down from the vibrating platform, inorder subsequently to recycle the latter. Because the same element isused to load the vibrating platform with parts and to collect the partsfalling down from the vibrating platform, the necessity for separateparts transport devices to feed back the parts that have fallen downfrom the vibrating platform, and their renewed feeding to the vibratingplatform are dispensed with. As opposed to previously known partsfeeders, the parts feeder according to the invention therefore manageswithout any parts transport devices for horizontal parts conveyance,such as conveyor belts, linear rails or the like. This permits anextremely simple and space-saving construction of the parts feederaccording to the invention. In addition, as a result of the eliminationof the conveyor belts and linear rails, which are susceptible toblockage, the risk of blockage of the entire parts feeder can be reducedsubstantially.

The vibrating platform and the parts recirculation element can be movedrelative to each other. In order to produce the relative movement,either the vibrating platform can be arranged to be substantially fixedto a frame of the parts feeder, and the parts recirculation element canbe arranged to be movable with respect to this frame and therefore tothe vibrating platform. Or, vice versa, the parts recirculation elementcan be arranged to be fixed to the frame of the parts feeder and thevibrating platform can be arranged to be movable on the frame. It goeswithout saying that, in principle, both the parts recirculation elementand the vibrating platform can be arranged to be movable on the frame ofthe parts feeder, in order to provide relative movement between theparts recirculation element and the vibrating platform.

The parts recirculation element can be designed like a trough, that isto say as a container open at the top and having a bottom and sidewalls, in order to assist the collection of the parts in the secondposition. The parts can then simply fall down from above into thetrough-like parts recirculation element.

The parts recirculation element is preferably provided with aninterchangeable upper part, the upper side of this upper part beingadapted to a desired number of parts which, in the first position of theparts recirculation element, are conveyed from the parts recirculationelement to the vibrating platform in order to load the vibratingplatform.

According to a preferred embodiment of the invention, the partsrecirculation element is arranged in the immediate vicinity of thevibrating platform and can be displaced in the manner of a lift in thevertical direction between the first position for loading the vibratingplatform and the second position for collecting the parts. In the first,raised position, the parts recirculation element is arranged at a levelthat is increased with respect to the vibrating platform in such a waythat the parts are conveyed from the parts recirculation element to thevibrating platform substantially by the force of gravity. In the second,lowered position, the parts recirculation element is arranged at a levelthat is lower with respect to the vibrating platform in such a way thatthe parts that fall down from the vibrating platform as a result of thevibration of the latter fall onto or into the parts recirculationelement substantially on account of the force of gravity. In order toload the vibrating platform with parts, a parts recirculation element oftrough-like design can be provided with a lateral outlet opening. As analternative, a parts recirculation element can also be designed like afunnel, the vibrating platform being arranged at the center of thefunnel-like parts recirculation element. It is preferable for the bottomof the parts recirculation element, carrying the parts, to be inclineddownward toward the vibrating platform so that the parts flow toward thevibrating platform merely on account of the force of gravity. Thisrepresents an extremely simple possible way of conveying parts withinthe parts recirculation element.

In a parts feeder for a robot, having a selection zone accessible to therobot, and a device for changing the orientation and/or the position ofthe parts stochastically, the device for changing the orientation and/orthe position of the parts stochastically can be a vibrating platformconstructed at the same time as a selection zone, the vibrating platformbeing constructed to execute vibrating movements with a singlemechanical degree of freedom. In this case, the number of degrees offreedom is, as usual, understood to mean the number of mutuallyindependent determinants (coordinates) which are needed in order todetermine the system uniquely. For example, a mass point that can movefreely in space has three mechanical degrees of freedom, while a masspoint that moves on a curve has one degree of freedom. Since, in thecase of a parts feeder according to this variant of the invention, theentire vibrating platform has to be moved simply with a singlemechanical degree of freedom, the vibrating platform itself, the drivefor producing the vibrating movement us [sic] therefore the entire partsfeeder can be constructed extremely simply and cost-effectively. Forexample, a cost-effective, simple vibrating device can be used for thedrive of the vibrating platform, as is common for constructionalmachines. It is clear that this aspect of the invention does notnecessarily have to be used in connection with the parts recirculationelement that can be moved with respect to the vibrating platform inorder to recirculate the parts.

The vibrating platform that can be moved with a single mechanical degreeof freedom is preferably constructed to execute vibrating movementssubstantially in the vertical direction, so that the vibrations or thevibrating movements are carried out only in the vertical direction. Asopposed to previous parts feeders, the parts are then not specificallyconveyed in a horizontal direction by the vibrating platform. Thevibrating platform merely has the function of separating the parts bythrowing the latter repeatedly upward and of changing their orientationand their position stochastically. In addition, it is advantageous ifthe vibrating platform is provided with a drive device for generatingthe vibrating movement, which permits optional setting of the frequency,the amplitude and the duration of the vibrating movement. The frequency,the amplitude and the duration of the vibrating movement can inparticular be set by software in order to provide a programmable controldevice to control the vibrating platform. By setting the frequency, theamplitude and the duration of the vibrating movement, the parts feedercan be adapted in a simple way to different parts forms. Beforeprocessing parts with a new form, these parameters can be optimized, ina setting or test phase, for the greatest possible efficiency withregard to the desired orientation and/or position of the parts to beprocessed.

The vibrating platform of a parts feeder according to the invention canalso be provided with an interchangeable supporting surface on the upperside of the platform, it being possible for the supporting surface(“tooling plate”), on which the parts come to lie, to be structured andto be adapted to specific parts forms and/or specific parts ranges. Thisprovides the possibility of arranging the parts, by means of stochasticvibration, in an orientation whose probability of occurrence iscomparatively low. In this way, for example, parts can be arranged tostand on their narrow side. In addition to the abovementioned settableparameters of the vibrating movement, the interchangeable supportingsurface permits further simple possible adaptation of the parts feederto different parts forms, by the supporting surface being able to beinterchanged for a new parts form and replaced by a supporting surfaceadapted to the new parts form.

According to a further preferred embodiment of the invention, the partsfeeder further comprises a detection device for detecting theorientation and the position of the parts on the vibrating platform, andalso data transmission means for transmitting the detected orientationsand positions to the robot, in order to assist the selection of theparts by the robot on the vibrating platform, serving at the same timeas a selection zone. The detection device preferably comprises means foroptical orientation and position detection and also means forilluminating the vibrating platform, the optical detection means and theillumination means being arranged in a common housing. The housing canbe provided with a viewing opening aimed at the platform, the housingpreferably being simply open in the direction of the platform, in orderto prevent disruption caused by the influence of external light.Furthermore, the housing can be movable over the vibrating platform, inorder to detect the orientation and the position of the parts. For thispurpose, the housing can be arranged on a substantially horizontalrunning rail arranged above the vibrating platform. By means of thecamera, which can be moved over the vibrating platform together with theillumination means in a housing, the parts feeder becomes independent ofthe robot to which it feeds the parts. In the case of a parts feederwith a stationary camera and a robot which moves in the visible areabetween the camera and the selection zone, this is not so.

According to a method according to the invention for operating a partsfeeder for a robot, the following steps are carried out one afteranother in a continuous endless procedure: in a first step, a vibratingplatform constructed so as to change the orientation and/or the positionof the parts stochastically by vibrating, and a parts recirculationelement, are moved relative to each other into a first position, thevibrating platform then being loaded with parts from the partsrecirculation element in this first position. In a second step, thevibrating platform and the parts recirculation element are movedrelative to each other into a second position to collect parts whichfall down from the vibrating platform. The parts are collected in or onthis parts recirculation element. In a third step, the orientationand/or the position of the parts on the vibrating platform is/arechanged stochastically by vibrating the vibrating platform, any partsthat fall down from the vibrating platform being collected by the partsrecirculation element. In a fourth step, the orientation and theposition of the parts on the vibrating platform are detected, and thecorresponding orientation and position data are transmitted to therobot. In a fifth step, depending on the transmitted orientation andposition data of the parts, any parts with a favorable orientation andposition are gripped by the robot on the vibrating platform, serving atthe same time as a selection zone, and are conveyed away, that is to sayselected. In a sixth step, the number of parts remaining on thevibrating platform is determined, a return then being made either to thethird step or to the first step, depending on this number. If the numberof parts remaining on the vibrating platform is lower than a predefinedminimum number, then a return is made to the first step, otherwise tothe third step.

In a variant of the method, instead of the control by the sixth step,the return to the first step can be controlled by the expiry of apredefined time since the last execution of the first step. In anothervariant, this return to the first step can be controlled by the areacoverage of the vibrating platform.

In the case of a parts recirculation element designed like a trough, themethod can further comprise a seventh step, which is executed after thesixth step before the return to the first step, the number of parts inthe parts recirculation element being determined in this seventh stepand the parts recirculation element being filled with new parts on thebasis of this number. As an alternative to putting the new parts intothe trough-like parts recirculation element, the new parts can also beconveyed directly onto the vibrating platform by an additional conveyingdevice.

The method according to the invention for the operation of a partsfeeder for a robot is preferably carried out completely automatically,so that no manipulations by hand are necessary.

The following detailed description of the present invention, inconjunction with the appended drawings, serves only as an example forbetter understanding of the invention, and should not be interpreted asrestricting the protective range of the patent claims. For those skilledin the art, further advantageous types of embodiment and combinations offeatures can readily be recognized from the following description inconnection with the appended drawings and all of the patent claims, butalways still lie within the scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings used to explain the exemplary embodiments:

FIG. 1 shows a preferred type of embodiment of a parts feeder accordingto the invention for a robot, from above in a simplified plan view;

FIG. 2 shows the parts feeder from FIG. 1 in a simplified side viewsectioned along the line A—A;

FIG. 3 shows a diagrammatic, schematic representation of the progress ofa preferred type of embodiment of the method according to the inventionfor the operation of a parts feeder for a robot.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The parts feeder illustrated in FIGS. 1 and 2 for a robot (notillustrated) comprises a frame with a base 22, to which a solid, hollowcylindrical column 23 projecting vertically upward is fixed. Permanentlyfitted in the upper area of the column 23 is a housing 41 comprising thedrive of a vibrating device. The housing 41 is substantially arranged inthe hollow interior of the hollow cylindrical column 23. The vibratingdevice, in the form of a pneumatic vibrator such as is in widespread usefor applications in constructional machines, further comprises a basepart 42, which can be moved with respect to the vibrator housing 41,being excited into substantially vertically oriented vibration orshaking movements by the vibrator drive. (The base part, actuallycovered in the plan view of FIG. 1, is indicated in FIG. 1 by brokenlines.) The vibrator 41, 42 is provided with a vibrator control device,which permits computer-controlled setting of the frequency, theamplitude and the duration of the vibration.

Arranged on the base cart 42 of the vibrator is a supporting surface 43similar to a plate (“tooling plate”), which serves as a support for theparts to be fed to the robot by the parts feeder. The supporting surface43 is permanently connected to the base part 42 and, together with thelatter, forms a vibrating platform 40 which can be moved with vibratingmovements with respect to the vibrator housing 41 and the column 23, inorder in a vibrating operation to change the orientation and/or theposition of the parts lying on the vibrating platform 40 or thesupporting surface 43 stochastically. If required, the supportingsurface 43 can be detached from the base part 42 and replaced by adifferent supporting surface, in order to adapt the vibrating platform40 to different parts forms. Overall, the vibrating platform 40 ismounted on the column 23 in such a way that it can be movedsubstantially only in the vertical direction with respect to the column23, in order to be able to execute shaking or vibrational movements inthe vertical direction. In the horizontal direction, on the other hand,the vibrating platform 40 is arranged to be undisplaceable with respectto the column 23.

To the side of the vibrating platform 40, immediately adjacent thereto,a parts recirculation element 30 or a parts conveying element 30 isarranged, which serves to convey the parts to be fed to the robot by theparts feeder. The parts recirculation element 30 can be displaced withrespect to the column 23 and with respect to the vibrating platform 40in the manner of a lift in the substantially vertical direction betweena first position for loading the vibrating platform 40 with parts fromthe parts recirculation element 30 and a second position for collectingparts which fall down from the vibrating platform 40.

For the purpose of displacement in the vertical direction, the partsrecirculation element 30 is guided in the vertical direction by a linearguide fitted to the column 23, and is driven in the vertical directionby a lifting drive 26 acting between the column 23 and the dartsrecirculation element 30 in the form of a pneumatic piston/cylinderarrangement.

On the side of the parts recirculation element 30 remote from thevibrating platform 40, to the side of and adjacent to said partsrecirculation element 30, there is arranged a parts storage container 50or a parts reservoir 50, which is designed to accommodate a largequantity of parts to be fed to the robot. The bottom 51 of the partsstorage container 50 is inclined falling toward the side of the partsrecirculation element 30 in such a way that the parts slip toward thisside of the parts storage container 50 merely on account of the force ofgravity. The parts storage container 50 therefore simultaneously has thefunction of a feed chute which conveys the parts toward the partsrecirculation element 30.

In relation to the conveying or flow direction of the parts in the partsstorage container 50, the parts recirculation element 30 forms a frontboundary wall of the parts storage container 50, which can be displacedin the vertical direction in the manner of a slider in order optionallyto open or to close the parts storage container 50. When the partsrecirculation element 30 is in the first position (illustrated by brokenlines in FIG. 2) for loading the vibrating platform 40 with parts fromthe parts recirculation element 30, then the parts storage container 50is bounded and closed by that side of the parts recirculation element 30which is oriented toward the parts storage container 50. In the second,lowered position of the parts recirculation element 30, illustrated inFIG. 2 by continuous lines, the parts storage container 50 is open tothe front, in the direction of the parts recirculation element 30 and ofthe vibrating platform 40. In this second position, the partsrecirculation element 30 serves firstly to collect parts which fall downfrom the vibrating platform 40. Secondly, in this second position, atthe same time parts can flow from the parts storage container 50 ontothe parts recirculation element 30. On the next occasion on which theparts recirculation element 30 is raised into the first position, allthe parts lying on the parts recirculation element 30, that is to sayboth the parts that have fallen down from the vibrating platform 40 andthe parts which have flowed from the storage container 50 onto the partsrecirculation element 30, can then be conveyed onto the vibratingplatform 40.

The parts recirculation element 30 has a substantially rectangular upperside, on which the parts slipping out of the parts storage container 50and/or the parts falling down from the vibrating platform 40 come tolie. This upper side of the parts recirculation element 30 has thefunction of a parts carrying surface for carrying the parts. When theparts recirculation element 30 is displaced upward, this parts carryingsurface has, in relation to the parts lying on it, the function of aconveying platform or a lifting platform, on which the parts areconveyed upward.

The parts recirculation element 30 is composed of two parts, namely alower part 32, which is connected to the lifting device 26 mentionedabove, and an upper part 31, which has the parts carrying surfacementioned above or the upper side of the parts recirculation element 30.The upper part 32 can be detached from the lower part 31 as required andreplaced by a different upper part. This different upper part can havean upper side of a different shape. By means of appropriateconfiguration of the upper side of the [sic] of the upper part (andtherefore of the upper side of the parts recirculation element 30), itis possible to determine the quantity of parts which is conveyed ontothe vibrating platform 40 by means of the parts recirculation element 30during each lifting operation. For example, this upper side can be ofwedge-like design, with a face falling toward the vibrating platform 40and a face falling toward the parts storage container 50. During eachlifting operation, only those parts lying on the face falling toward thevibrating platform 40 will then be conveyed onto the vibrating platform40.

The substantially flat upper side of the parts recirculation element 30,serving as the parts carrying surface, is inclined downward toward theside of the vibrating platform 40. In the second, lowered position ofthe parts recirculation element 30, the inclined upper side of the partsrecirculation element 30 forms a front extension of the bottom 51 of theparts storage container 50, the parts slipping from the parts storagecontainer 50 onto the upper side of the parts recirculation element 30on account of the force of gravity. The inclination of the upper side ofthe parts recirculation element 30 is chosen in such a way that when theparts recirculation element 30 is in the first (raised) position forloading the vibrating platform 40 with parts from the partsrecirculation element 30, the parts on the upper side of the partsrecirculation element 30 flow or slip toward the vibrating platform 40merely on account of the force of gravity.

Along its vertical displacement path, the parts recirculation element30, having a substantially rectangular cross section, is enclosed onthree sides by vertical boundary walls 45, 46, 47, which are permanentlyfitted to the column 23. In the second, lowered position of the partsrecirculation element 30, these boundary walls 45, 46, 47 form avertical shaft closed on three sides, into which the parts falling downfrom the vibrating platform 40 fall. The shaft cross section correspondsto the cross section of the parts recirculation element 30. The bottomof the shaft is formed by the upper side of the parts recirculationelement 30. On the fourth side of the parts recirculation element 30,toward the parts storage container 50, the shaft is open.

The shaft wall 47 arranged between the vibrating platform and the partsrecirculation element 30 extends downward from the level of thevibrating platform 40 or its supporting surface 43. In the first, raisedposition of the parts recirculation element 30, the entire upper side ofthe parts recirculation element 30 projects beyond the upper edge ofthis wall 47. The upper side of the parts recirculation element 30 inthis first position lies at a higher level than the vibrating platform40, so that the parts slip onto the vibrating platform 40 from the partsrecirculation element 30 over the upper edge of the shaft wall 47located between them. In the second, lowered position of the partsrecirculation element 30, the upper side of the parts recirculationelement 30 lies at a lower level than the level of the vibratingplatform 40, and the parts fall from the vibrating platform 40 onto theparts recirculation element 30 over the upper edge of the shaft wall 47lying between them.

The two other shaft walls 45, 46 are formed as an extension of avertical boundary wall 44 which rests closely against the vibratingplatform 40 and encloses the latter in a U shape. This boundary wall 44is also permanently fitted to the column 23 of the parts feeder. Itextends upward beyond the level of the vibrating platform 40 andprevents the parts on the sides closed off by the boundary wall 44 beingable to fall down from the vibrating platform 40. The parts can merelyfall down from the vibrating platform 40 on the side facing the partsrecirculation element 30. The two arm-like extensions 45, 46 of thisboundary wall 44, with a U-shaped outline, enclose the partsrecirculation element 30 on two sides and in each case form a side wall45, 46 of the shaft mentioned above. They extend upward beyond upperside of the parts recirculation element 30 in its first, raisedposition, in order to prevent the parts being able to fall down from theparts recirculation element 30 on a side other than that facing thevibrating platform 40.

The parts feeder illustrated in FIGS. 1 and 2 is also provided with adetection device for detecting the orientation and the position of theparts of the vibrating platform, and also with data transmission means,in order to transmit the detected orientations and positions to therobot, in order that the latter can select the parts on the vibratingplatform 40 on the basis of the orientation and position data receivedfrom the detection device. The detection device comprises a camera foroptical orientation and position detection and also means forilluminating the vibrating platform 40, the camera 61 and theillumination means 62 being arranged in a common housing 60. The housingis provided with a viewing and illumination opening pointing toward thevibrating platform. Otherwise, the housing is sealed so as to be opaque,in order to prevent disruption arising from the influence of externallight. The camera and illumination housing can be moved over thevibrating platform on two substantially horizontal guide rails, in orderto detect the orientation and the position of the parts.

For the operation of the parts feeder illustrated in FIGS. 1 and 2 for arobot, the following steps are executed one after another in acontinuous endless procedure, which is illustrated diagrammatically inFIG. 3.

In a first step 1, the parts recirculation element 30 is brought intoits first position for loading the vibrating platform 40 with parts fromthe parts recirculation element 30, and the vibrating platform 40 isloaded with parts from the parts recirculation element 30. In this case,the parts flow directly from the parts recirculation element 30 onto thevibrating platform 40 merely on account of the force of gravity.

In a second step 2, the parts recirculation element 30 is brought intoits second position for collecting parts which fall down from thevibrating platform 40.

In a third step 3, in a shaking or vibration operation, the vibratingplatform 40 is vibrated in accordance with the set frequency, amplitudeand duration. As a result of the vibrating movement of the platform 40,the parts lying on the vibrating platform 40 are thrown up repeatedly,in order to separate them and to change their orientation and theirposition stochastically. During the shaking operation, individual partscan fall down from the vibrating platform 40, over its edge facing theparts recirculation element 30, from the platform 40, falling directlyonto the parts recirculation element 30.

In a fourth step 4, with the vibrating platform 40 at rest, theorientation and the position of the parts on the vibrating platform 40are then detected, by the housing with the camera and the illuminationmeans being moved over the vibrating platform 40. At the same time, thevibrating platform 40 is illuminated by the illumination means, and thesurface of the vibrating platform 40 is scanned optically by the camera.By means of a suitable image recognition device, the orientation and theposition of the parts on the vibrating platform 40 are determined on thebasis of the optical data determined by the camera, and the parts whichare oriented and positioned suitably for selection by the robot aredetermined, and their orientation and position data are transmitted tothe robot.

In a fifth step 5, the determined orientation and position data arefirst used to check whether there are parts suitable for selection bythe robot on the vibrating platform 40. If this is so, in a part step5.1, depending on the transmitted orientation and position data, theparts with a favorable orientation and position are selected by therobot, that is to say they are gripped directly by the robot on thestationary vibrating platform 40 and are conveyed away for furtherprocessing. If there are no suitable parts on the vibrating platform 40,the part step 5.1 is left out.

In a sixth step 6, first of all the number of parts remaining on thevibrating platform 40 is determined. Then, depending on this number, areturn is made either to the third step or to the first step. If thenumber of parts remaining on the vibrating platform 40 is lower than apredefined minimum number, then a return is made to the first step,otherwise to the third step.

It is not absolutely necessary for all the steps of the method to becarried out completely one after another; instead, individual steps canalso be carried out in an at least partly overlapping manner, in orderto accelerate the progress of the method.

In summary, it is to be recorded that, by means of the invention, aparts feeder is provided which is simple in design terms, space-savingand flexible in relation to different parts forms.

What is claimed is:
 1. A parts feeder for a robot, having a selectionzone accessible to the robot, comprising: a vibrating platform forchanging the orientation and/or the position of the partsstochastically, said vibrating platform comprising the selection zone, adevice with a parts recirculation element for recirculating the parts,and a drive for displacing the parts recirculation element and/or thevibrating platform into two different positions relative to each other,so that in the fist position the parts from the parts recirculationelement are conveyed to the vibrating platform by the force of gravityand that in the second position, the parts which fall down from thevibrating platform are collected by the parts recirculation element. 2.The parts feeder according to claim 1, wherein the parts recirculationelement is designed in a trough form in order to assist the collectionof the parts in the second position.
 3. The parts feeder according toclaim 1, wherein the parts recirculation element is provided with aninterchangeable upper part, an upper side of said upper part beingadapted to a desired number of parts which, in the first position of theparts recirculation element, are conveyed from the parts recirculationelement to the vibrating platform in order to load the vibratingplatform.
 4. The parts feeder according to claim 1, wherein the partsrecirculation element is arranged in an immediate vicinity of thevibrating platform and can be displaced in a vertical direction betweenthe first position for loading the vibrating platform and the secondposition for collecting the parts, in the first position the partsrecirculation element being arranged at a level that is increased withrespect to the vibrating platform and in the second position the partsrecirculation element being arranged at a level that is lower withrespect to the vibrating platform.
 5. The parts feeder according toclaim 1, wherein the vibrating platform is provided with aninterchangeable supporting surface on an upper side of the platform,such that a surface structure of the supporting surface can be matchedto the parts form.
 6. The parts feeder according to claim 1, wherein thevibrating platform is effective to execute vibrating movements with asingle mechanical degree of freedom.
 7. The parts feeder according toclaim 6, wherein the vibrating platform is designed to execute vibratingmovements substantially in the vertical direction.
 8. The parts feederaccording to claim 6, wherein the vibrating platform is provided with avibrating device for generating the vibrating movement, which permitsoptional setting of the frequency, the amplitude and the duration of thevibrating movement.
 9. The parts feeder according to claim 1, furtherincluding a detection device for optical detection of the orientationand the position of the parts on the vibrating platform, and datatransmission means for transmitting the detected orientation andposition data to the robot.
 10. The parts feeder according to claim 9,further including means for illuminating the vibrating platform, thedetection device and the illumination means being arranged in a commonhousing.
 11. The parts feeder according to claim 10, wherein the housingcan be moved over the vibrating platform, in order to detect theorientation and the position of the parts.
 12. A method for feedingparts to a robot, the following steps carried out in a continuousendless procedure, the steps comprising: a) in a first step, a vibratingplatform for changing the orientation and or the position of the partsstochastically by vibrating, and a parts recirculation element, aremoved relative to each other into a first position, the vibratingplatform then being loaded with parts from the parts recirculationelement in this first position; b) in a second step, the vibratingplatform and the parts recirculation element are moved relative to eachother into a second position in order that parts that fall down from thevibrating platform can be collected by the parts recirculation element;c) in a third step, the orientation and/or the position of the parts onthe vibrating platform can be changed stochastically by vibratingplatform, any parts that fall down from the vibrating platform beingcollected by the parts recirculation element; d) in a fourth step, theorientation and the position of the parts on the vibrating platform aredetected, and the corresponding orientation and position data aretransmitted to the robot; e) in a firth step, depending on thetransmitted orientation and position data, any parts with a favorableorientation and position are gripped by the robot on the vibratingplatform and conveyed away; f) in a sixth step, the number of partsremaining on the vibrating platform is determined, a return then beingmade either to the third step or to the first step, depending on saidnumber of parts.